Thanks BO0m we don't of course know the wind, which would also effect groundspeed. Just a wild thought, but is it possible that the pitch angle might be the start of an attempted go-around?
If I understood correctly the procedure would be to fly Flaps 15 at around 150 knots downwind, then turn base reducing speed and selecting Flaps 30 to aim for a Vref 107 + 5(min). There is no auto thrust so power would set by the pilot flying, probably near idle as they reduced speed. If they got distracted managing the final turn and did not increase power, speed would decay pretty rapidly. Also if you were below 500 feet the stuck pusher would be inhibited. Is that a reasonable summary?
Go-arounds are one of the worst flown (standard) manoeuvres. It seems a stretch that they would not firewall the thrust levers, but I have heard of weird reactions in similar situations.